This invention is directed to siloxane surfactants and to the formation of vesicles from siloxane surfactants. More particularly, the invention is directed to the use of vesicles formed from siloxane surfactants for the entrapment of water-soluble and water-insoluble substances.
The first problem to be solved by the present invention is to find a siloxane molecule which is able to form vesicles. The second problem to be solved by the present invention is to develop a use of such vesicles formed from siloxane surfactants for substance entrapment.
Because of the nature of the siloxane linkage, siloxane surfactants do not follow the usual rules of surfactant activity with regard to such things as aggregate formation and solubilization. Therefore, to even find a siloxane molecule which is able to form vesicles is quite surprising and unexpected. What is even more surprising and unexpected, is that having once pinpointed a particular siloxane molecule for vesicle formation, that the vesicle formed from the siloxane surfactant would also be useful to entrap substances.
The problems outlined above are solved according to the present invention, by the careful investigation and selection of only certain particular siloxane molecules which have been found to be capable of vesicle formation; and their use in substance entrapment.
The advantages and benefits to be derived by the use of siloxane surfactants in vesicle formation and substance entrapment, include the fact that siloxanes possess a non-hydrocarbon character, and therefore provide a different set of physical properties than is currently available with hydrocarbon-based surfactant molecules. Secondly, siloxane surfactants have been found to form vesicles "spontaneously" on contact with water, and therefore they eliminate the use of energy intensive processes such as sonification, which are required for non-siloxane based surfactants. Thirdly, because the siloxane backbone offers chemically reactive sites, it is possible to easily exploit the formation of polymerized vesicles.